Remote control device



' sept. s, 1942.

KQ WILHELM REMOTE CONTROL DEVICE Filed June 19, 1940 I I I I I I I I I I I I I 67E/@W16 I I I I I I I ,Erft/rf) INVENTOR ATTORNEY Patented Sept. 8, 1942 REMOTE CONTROL DEVCE Karl Wilhelm, Berlin, Germany, vested in the Alien Property Custodian Application June 19, 1940, Serial No. 341,283 In Germany January 25, 1939 (Cl. Z50-40) Claims.

In the hitherto known arrangements for the remote control oi high frequency apparatus as, for instance, a receiver energized from across the alternating current network there is used at the place of control an auxiliary oscillatorsince direct current impulses cannot be transmitted over the network-whereby the oscillations of said auxiliary oscillator are transmitted to the apparatus to be controlled from a distance, and release at this place controlling actions.

In many cases it is desired, however, to devise the arrangement at the place of control as simple as possible and to admit of a larger amount of means only for the control means provided for the apparatus since at this place operating voltage sources and the like are already present. This is especially true where several control places are provided, or where the remote control box is to be connected for the remote control to the one point and then to the other point of the line.

According to the present invention this problem is solved in that the apparatus whose remote control is desired is provided with an auxiliary oscillator which is coupled with the line and that at the place of control an absorption circuit which is tuned to the frequency of the Aauxiliary oscillator can be inserted at will into the line and that the amplitude variations of the auxiliary oscillator thereby effected serve for the remote control. The insertion is to take place more especially such that, as desired, different series of absorption impulses can be rendered eective whereby, for instance, a definite impulse series is assigned to each station to which the receiver is to be tuned by remote action. The respective impulse series of the amplitudes of the auxiliary oscillator may serve for controlling a stop movement which advances the tuning means (the variable condenser) of the receiver or switches elements of the oscillatory circuit of the receiver which determine the frequency.

Primarily the arrangement shall be adapted in such a manner that on switching-in the absorption circuit at the place of control, the oscillations of the auxiliary oscillator cease.

An example of construction according to the present invention is shown in the accompanying drawing, 'Connected across the double line Zi, Z2 of the alternating current network are the throw-in switch S to the battery eliminator N of the radio receiver E to be controlled from a distance and the coupling coil La placed in series to the switch S. The coil La is coupled to the oscillatory circuit of the auxiliary oscillator I-I which is tuned to a high audible frequency (for instance, 10,000 cycles). The direct potential appearing at the grid of the oscillator tube relative to the grounded cathode, which direct potential has a high negative value when oscillations appear, but zero value when the oscillations cease, is applied across the low-pass filter F to the control grid of an additional amplifier tube V whose plate circuit contains the relay coil R of a step movement W shown in a schematical manner only. The contact K of the step movement is arranged to advance one step each time relay R is energized. Contact K is shown in the position of rest in which position the variable condenser C is connected in parallel to the coil L which in the present case is assumed to be the coil of the oscillatory circuit of the local oscillator of the receiver. (It is lhere assumed that the superheterodyne receiver E has an aperiodic high-frequency amplifier, or a semif periodic high-frequency amplifier. The receiver may be, for instance, a single range superheterodyne.) In the other positions of the switching contact K the variable condenser is disconnected, and one of the xed condensers Ci, C2 or C3 will be connected in parallel to L so that the receiver is tuned to a predetermined respective radio transmitter. It is to be presupposed that after a denite number of progressing steps the position of rest will be assumed again.

At the remote control point there lies in parallel to the network line the series connection of a coil L', condenser C and switching key T maintained in the open position by the spring S. The circuit containing L', C', the coupling coil La, the bridging condenser Co which is in parallel to the input of the battery eliminator and is preferably a short circuit for the auxiliary frequency, and also the network impedance are tuned to the frequency oi' the auxiliary oscillator H. The resonance resistance of the circuit must be suciently low (a few ohms).

For the remote tuning to a definite transmitter, such as that corresponding to the receiver when tuned by condenser C2, the key T will be depressed twice in short successions while the receiver E is energized. Consequently the oscillation of the auxiliary oscillator H is interrupted twice in brief successions and the tube V which normally has a highly negative grid biasing potential applied thereto receives twice in short successive periods zero grid biasing potential so that two current impulses can pass through the coil R which advance the switching contact K by two steps. In this manner the capacitance C2 is placed in parallel to the oscillator coil L and the remote tuning to the desired transmitter is thereby carried out.

I claim:

1. In a system operable over an electric power supply network for the remote control of a radio received which is provided with tuning mechanism, a stepping relay for controlling the adjustment of said tuning mechanism, a rst discharge tube which is normally inactive having said stepping relay included in its output circuit, a second discharge tube and circuits Aassociated therewith for normally maintaining said tube in an oscillating condition, means for interconnecting said tubes so that the rst tube is made nonconducting during the oscillating condition of the second tube and conducting during the non-oscillating condition of the second tube, means for coupling said second tube to the power supply network, and means at a remote point also coupled to the power supply network effective to stop the second tube from oscillating whereupon the rst tube becomes conducting to operate the stepping relay.

2. In remote control apparatus operable from a power supply line for controlling the operation of a radio receiver, a discharge tube oscillator which is normally in the oscillating condition, means for coupling the oscillator to the power supply line, a control tube coupled to said oscillator adapted to draw current only when the oscillator is in its non-oscillating condition, a magnetic relay included in the anode circuit of the control tube for adjusting the tuning of the radio receiver, and means remote from the receiver adapted upon being connected across the power supply line to disable the oscillator whereupon the control tube becomes operative to energize the magnetic relay which in turn becomes operative to adjust the tuning of the receiver.

3. In remote control apparatus operable from a power supply line for controlling the operation of a radio receiver, said receiver being provided with a plurality of semi-iixed reactances, the connection into circuit of any one of which is adapted to tune the received to a predetermined frequency, a discharge tube oscillator which is normally in the oscillating condition, means for coupling the oscillator to the power supply line, a control tube coupled to said oscillator adapted to be biased to plate-current cut-off during the normal operation of the oscillator and to draw current when the oscillator is in its non-oscillating condition, a stepping relay included in the plate circuit of the control tube for sequentially connecting the tuning reactances, and means remote from the receiver and under the control of an Operator adapted upon being connected across the power supply line to interrupt operation of the oscillator whereupon the control tube becomes operative to energize the stepping relay a number of times corresponding to the number of interruptions of the oscillator.

4. In remote control apparatus operable over an electric power supply line, a space discharge device having an anode circuit and a grid circuit, said anode circuit including a relay responsive to the flow of current in said anode circuit, an electronic tube oscillation generator circuit connected to said grid circuit and arranged in normal operation to bias said space discharge device to cut off, a tank circuit for said oscillation generator, means for coupling the tank circuit to the power supply line, reactance means, keying means for connecting said reactance means to said power supply network, said reactance means acting upon connection thereof to the power supply network to cause the oscillations generated by said oscillation generator to cease and thereby remove the cut-off bias from said amplifier tube.

5. In a remote control system operable over an electric power supply line, an electronic tube oscillator having an anode, a cathode, and a control electrode, a tank circuit comprising an inductance coil shunted by a tuning condenser, a connection between the anode of said tube and one end of said inductance coil, a condenser connecting the grid of said tube to the other end of said inductance coil, a source of direct current having its positive terminal connected to an intermediate point of said inductance coil and its negative terminal connected to said cathode, an impedance connected between the grid and cathode of said tube, a space discharge device having an anode, a cathode and a control electrode, an anode circuit for said device including a relay responsive to the flow of space current of said device, means for grounding said two cathodes, resistance means connected between said two control electrodes, a condenser connected between said first named cathode and the control electrode of said space discharge device, a coil coupled to said inductance coil, means connecting said coil across said power supply line, reactance means, keying means for connecting said reactance means across said power supply network at a point remote from the point at which said coil is connected, said reactance means together with said coil and the means for connecting the coil t0 the power supply line and at least that portion of the power supply network intermediate the two connections, forming a circuit which is resonant at substantially the frequency generated by said oscillator.

KARL WILHELM. 

